Messages in this thread | | | Date | Sat, 4 Dec 1999 12:22:58 -0700 | From | Richard Gooch <> | Subject | Re: Can't hardlink in different dirs. (BUG#826) |
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Alan Curry writes: > Richard Gooch writes the following: > > > >This misses the point. The proposed change would require me to make my > >inodes writable by others in order to let them make hard links. That's > >much worse than the problem you're concerned about. > > If you environment is sufficiently non-hostile that you don't worry > about the other users doing nasty things to you, then why don't you > just give everybody the root password?
Cough! There are levels of trust, you know. If someone does consume my quota, all I need to do is find out who did it (if I'm a mere mortal, I may have to ask my sysadmin for help), and then walk over to the comedian and threaten to remove their gonads through their throat.
Giving everyone the root password is entirely different. I wouldn't be able to store semi-sensitive information on said system. And the system would become a dogs breakfast of ad-hockery (too many cooks spoil the broth).
> But the fact that we don't have a working revoke() is the more > important problem. Forget local attacks. What about telnet to port > 80, type GET /~user/bigassgif.gif, and hit ^]^Z so the transfer will > never finish? rm needs some teeth for such situations.
Adding teeth isn't as simple as you'd think. Always doing a revoke(2) isn't a solution, becuase more often than not, you just want to schedule a file for deletion (i.e. the original definition of unlink(2)), because there might be legitimate programmes still holding the file open which you don't want to screw with.
So if you first do a regular unlink(2) (since that is the general case), even if someone has an open FD, it's too late, because you don't have a path to the file anymore.
So you see, there is no easy choice. Either you shoot first and ask questions later, in which case you have a bunch of innocent bystanders, or you tread carefully, in which case some undesirables get away with it.
BUT NOTE: there is no major damage done. A reboot will fix all references to open fds, and a simple script will clean up hard links. We're really talking about minor irritations, like flies on your back.
Personally, I'd rather swat them from time to time (with some getting through my defences), than coat myself with DDT.
Regards,
Richard.... Permanent: rgooch@atnf.csiro.au Current: rgooch@ras.ucalgary.ca
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